Two-piece compression piston ring of an internal combustion engine

Abstract

A compression ring assembly for a piston of an internal combustion engine includes a first compression ring and a second compression ring, with the second compression ring overlaid adjacent to and in abutting engagement with the first compression ring. When both the first compression ring and the second compression ring are uncompressed and in a free state, the second compression ring includes an outer second ring diameter that is greater than an outer first ring diameter of the first compression ring. Additionally, the first compression ring includes a first radial width that is greater than a second radial width of the second compression ring. A first gap of the first compression ring is positioned relative to a second gap of the second compression ring in a non-overlapping orientation.

The invention claimed is: 
     
       1. A piston assembly for an engine of a vehicle, the piston assembly comprising:
 an annular body having an outer side surface defining a groove; and 
 a ring assembly disposed within the groove, the ring assembly including:
 a first compression ring including a first ring outer face defining an outer first ring diameter; and 
 a second compression ring overlaid adjacent the first compression ring and including a second ring outer face defining an outer second ring diameter; 
 wherein the outer second ring diameter is larger than the outer first ring diameter when both the first compression ring and the second compression ring are disposed in a radially uncompressed condition; and 
 wherein the first compression ring includes a first ring cut defining a first ring gap extending radially across the first compression ring, and the second compression ring includes a second ring cut defining a second ring gap extending radially across the second compression ring, wherein the second ring gap is larger than the first ring gap when both of the first compression ring and the second compression ring are disposed in the radially uncompressed condition. 
 
 
     
     
       2. A piston assembly as set forth in  claim 1  wherein the first compression ring includes a radial spring tension related to a width of the first spring gap when the first compression ring is disposed in the radially uncompressed condition, the second compression ring includes a radial spring tension related to a width of the second spring gap when the second compression ring is disposed in the radially uncompressed condition, and wherein the spring tension of the first compression ring and the second compression ring increases with an increase in the width of the first gap and the width of the second gap respectively. 
     
     
       3. A piston assembly as set forth in  claim 2  wherein the second compression ring includes a higher radial spring tension than the first compression ring. 
     
     
       4. A piston assembly as set forth in  claim 1  wherein the first ring gap is equal to the second ring gap when both the first compression ring and the second compression ring are disposed in the radially compressed condition. 
     
     
       5. A piston assembly as set forth in  claim 4  wherein the outer second ring diameter is equal to the outer first ring diameter when both the first compression ring and the second compression ring are disposed in a radially compressed condition. 
     
     
       6. A piston assembly as set forth in  claim 1  wherein the first ring gap and the second ring gap are angularly offset relative to each other in a non-overlapping orientation. 
     
     
       7. A piston assembly as set forth in  claim 6  wherein the ring assembly includes a positioning mechanism securing the non-overlapping orientation between the first ring gap and the second ring gap. 
     
     
       8. A piston assembly as set forth in  claim 7  wherein the positioning mechanism is configured for allowing relative radially movement between the first compression ring and the second compression ring, and is configured for limiting relative angular movement between the first compression ring and the second compression ring. 
     
     
       9. A piston assembly as set forth in  claim 1  wherein the first compression ring defines a first radial width, and the second compression ring defines a second radial width, wherein the first radial width is greater than the second radial width. 
     
     
       10. A ring assembly for a piston of an internal combustion engine, the ring assembly comprising;
 a first compression ring including a first ring outer face defining an outer first ring diameter; and 
 a second compression ring overlaid adjacent the first compression ring and including a second ring outer face defining an outer second ring diameter; 
 wherein both the first compression ring and the second compression ring are configured for disposition within a singular groove defined by an annular body of a piston; 
 wherein the outer second ring diameter is larger than the outer first ring diameter when both the first compression ring and the second compression ring are disposed in a radially uncompressed condition; and 
 wherein the first compression ring includes a first ring cut defining a first ring gap extending radially across the first compression ring, and the second compression ring includes a second ring cut defining a second ring gap extending radially across the second compression ring, wherein the second ring gap is larger than the first ring gap. 
 
     
     
       11. A ring assembly as set forth in  claim 10  wherein the first compression ring includes a radial spring tension related to a width of the first spring gap when the first compression ring is disposed in the radially uncompressed condition, the second compression ring includes a radial spring tension related to a width of the second spring gap when the second compression ring is disposed in the radially uncompressed condition, and wherein the spring tension of the first compression ring and the second compression ring increases with an increase in the width of the first gap and the width of the second gap respectively. 
     
     
       12. A ring assembly as set forth in  claim 11  wherein the second compression ring includes a higher radial spring tension than the first compression ring. 
     
     
       13. A ring assembly as set forth in  claim 10  wherein the first ring gap is equal to the second ring gap when both the first compression ring and the second compression ring are disposed in the radially compressed condition. 
     
     
       14. A ring assembly as set forth in  claim 13  wherein the outer second ring diameter is equal to the outer first ring diameter when both the first compression ring and the second compression ring are disposed in a radially compressed condition. 
     
     
       15. A ring assembly as set forth in  claim 10  wherein the first ring gap and the second ring gap are angularly offset relative to each other in a non-overlapping orientation. 
     
     
       16. A ring assembly as set forth in  claim 15  wherein the ring assembly includes a positioning mechanism securing the non-overlapping orientation between the first ring gap and the second ring gap. 
     
     
       17. A ring assembly as set forth in  claim 16  wherein the positioning mechanism is configured for allowing relative radially movement between the first compression ring and the second compression ring, and is configured for limiting relative angular movement between the first compression ring and the second compression ring. 
     
     
       18. A ring assembly as set forth in  claim 10  wherein the first compression ring defines a first radial width, and the second compression ring defines a second radial width, wherein the first radial width is greater than the second radial width.